Ultrasonic method and apparatus for tissue grafting

ABSTRACT

The method and apparatus of grafting tissue, such as tissue in biological organisms such as humans, by the removal of live epidermal cells from one area of a body by ultrasonic means, and then transporting such cells in a suitable isotonic fluid suspension to the site where the fluidized cells are to find their new homes and then applying the cells thereto.

United States- Patent lnventor Appl. No.

Filed Patented Assignee Continuation-import of application Ser. No.

655,1 18, July 21, 1967, now Patent No. 3,526,219.

ULTRASONIC METHOD AND APPARATUS FOR References Cited Taylor, Rennie,Associated Press Article, Oct. 31, 1947, (copy in 3/1) PrimaryExaminer-Richard A. Gaudet Assistant Examiner--Kyle L. HowellAttorney-Leonard W. Suroff TISSUE GRAFIING 31 chhmsnnwing Figs ABSTRACT:The method and apparatus of grafting tissue, US. Cl 128/303, such astissue in biological organisms such as humans, by the 128/24 A, 128/305removal of live epidermal cells from one area of a body by ul- Int. Cl..A6lbl7/00, trasonic means, and then transporting such cells in asuitable A6lb 17/32 isotonic fluid suspension to the site where thefluidized cells Field of Search 128/303, are to find their new homes andthen applying the cells 303.], 305, 305.5, 24 A thereto.

0 96 60 9\ .95 67 F r' 36 35 L /02 50 755 2 a w H /5 a n In l l l :M 2I4 /3 25 28 4 PATENI ED SEP28 Ian SHEET 2 [IF 2 INVENTOR. LEWIS BALAMUTHMu). M

ATTORNEY ULTRASONIC METHOD AND APPARATUS FOR TISSUE GRAFTINGCROSS-REFERENCE TO RELATED APPLICATION This application is acontinuation-impart of my copending application Ser. No. 655,118, filedJuly 21, 1967, now US. Pat. No. 3,526,219, issued Sept. 1, 1970. andwhich entire subject matter of the copending application is incorporatedherein by reference as if fully herein set forth.

BACKGROUND OF THE INVENTION This invention relates broadly to graftingof tissue and more particularly to the method and apparatus for theselective removal of layers of tissue by ultrasonic means and thentransplanting the cells of the removed tissue to a new location.

Although the principles of the present invention are broadly applicableto the removal and transplanting of layers of low. compliant materials,the present invention is particularly adapted for use in conjunctionwith tissue in humans and hence will be so illustrated and will be sodescribed.

OBJECTIVES OF THE INVENTION An object of the present invention is toprovide an improved method and apparatus for grafting of tissue inhumans.

Another object of the present invention is to provide an improved methodand apparatus for progressively removing a layer of tissue from one areaof the body and transplanting the removed layer in the form of viabletissue to another area of the body.

Another object of the present invention is to provide an enclosed systemin which'healthy cells are removed in clusters using ultrasonic energyand transported in a fluid suspension and applied to another area of thehuman body.

Another object of the present invention is to provide an improved methodand apparatus for the removal of living organic cells in a rapid mannerwith the exertion of a minimum of physical energy and the depositing ofthe removed cells on the area requiring grafting.

Other objects and advantages of this invention will become apparent asthe disclosure proceeds.

SUMMARY OF THE INVENTION The outstanding and unexpected results obtainedby the practice of the method and apparatus of this invention areattained by a series of features, steps and elements assembled workingtogether in interrelated combination.

In my copending application, referred to above, I disclose thatmechanical elastic vibrations of hyperaccelerations of 50,000 g,properly transmitted to a biological organism in vivo may be employed toselectively separate living organic tissue from surrounding tissuewithout harmful effects to the surrounding tissue. This new principlehas been termed microchopping to more clearly define and illustrate myinvention.

I have now discovered that ultrasonic energy, properly controlled, mayremove the epidermal cells of the human body without substantial damagethereto and that the removed cells may be deposited on another area forgrafting thereof. The essential idea of this invention is the removal oflive epidermal cells from one area of the body by ultrasonic means, andthen transporting such viable cells in a suitable isotonic fluidsuspension through a conduit to the site where the fluidized cells areto find their new homes. Preferably the entire operation isself-confined so that no external means need contact the fluidsuspension from the time of formation to the time of grafting. This isparticularly useful for extensive graft areas such as are required dueto burns or diseases of the skin.

If desired the operation of obtaining the original cells may beperformed with a dermatome, a device for cutting tissue by nonultrasonicmechanical means, which has precision controls determining the depth tobe shaved" from the site, and the fluidized slurry of cells pumped in ahermetically sealed system to the transplanting or grafting site.

BRIEF DESCRIPTION OF THE DRAWINGS Although the characteristic featuresof this invention will be particularly pointed out in the claims, theinvention itself, and the manner in which it may be made and used, maybe better understood by referring to the following description taken inconnection with the accompanying drawings forming a part hereof, whereinlike reference numerals refer to like parts throughout the several viewsand in which:

FIG. 1, is a side elevational view in schematic form illustrating theinvention for grafting skin on a human;

FIG. 2, is a top elevational view of FIG. 1, illustrating therelationship of equipment;

FIG. 3, is an enlarged view illustrating the related components of theinvention for transporting the removed cells to the grafting site;

FIG. 4, is a side elevational view, partly broken away and in section,of the ultrasonic system utilized in accordancewith the presentinvention;

FIG. 5, is a greatly enlarged view in section of the ultrasonic tool andassociated guard in position during the removal process of a layer oftissue;

FIG. 6, is an enlarged view in section of the means of depositing theremoved cells on the grafting site;

FIG. 7, is a sectional view of another tool that can be used inaccordance with the invention; and

FIG. 8, is a view similar to FIG. 7, of another tool that can be used inconjunction with the invention.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to the drawings in detailand initially to FIGS. 1-6 thereof, it will be seen that the graftingapparatus 10 briefly includes in assembled relation to each othersupport means 12 having a plurality of vertical legs 13 and a top 14 onwhich the human 15 may be supported during the grafting process for theremoval of the live epidermal cells 17 from a removal site 18 in theform of individual cells or cell clusters and thereafter deposited on agrafting site 20, which sites may be on the same or different humans asin a transplant operation. Removal means 35 is adapted to remove thelayer of tissue from a portion of the removal site 18 of the human andthe forming means 60 cooperating therewith produces a fluidizedsuspension 62 (see FIG. 3) containing cells or cell clusters 17 and atreatment fluid 63 which is continuously formed and removed from theremoval site 18. Continuously or intermittently transferring meanstransfers the cells 17 of the fluidized suspension to the grafting site20 which is adapted to receive the cells thereon as by providing a layeror coating 120 of a medication and the depositing means coupled theretoapplies the cells 17 onto the grafting site 20, such that the graftedcells will form a new layer of tissue thereon.

Positioning Means The integrated operating components of the apparatus10 may be contained on or associated with positioning means 25 toprovide equipment mobility for a variety of positions withoutnecessitating changing of the position of the human 15, and includes abase 26 with a plurality of casters 27 for ease of movement and avertical leg 28 which extends therefrom for slidable engagement withbracket 29 which has secured thereto shelf 30 in any conventionalmanner. The bracket 29 is provided with a vertical bore for receivingthe vertical leg 28 and is provided with a slot 31 having a bolt 32extending therethrough to clamp the bracket in fixed position to thevertical leg 28. It is appreciated that other mechanical means may beemployed to produce the desired horizontal and vertical movement of theoperating components to transplant cells from various portions of thebody.

Removal Means The removal means 35 as illustrated in FIGS. 4 and 5, forultrasonically removing tissue from the removal site 18 may include anoscillation generator 36 mounted on the shelf 30 with a power cable 37,connected to an ultrasonic motor 41, for effecting the necessary highfrequency vibrations of the tool 43 having a sharp output edge orsurface 45. The ultrasonic motor 41 may be in the form of a hand pieceadapted for being hand held and generally comprising a tubular housing44 into which an insert unit 47 supporting the tool 43 may be partiallytelescoped. The generator is an oscillator adapted to produce electricalenergy having an ultrasonic frequency and having control knobs 39 and 40for respectively selecting and maintaining the frequency and intensityof the ultrasonic energy at a level below which substantial permanentdamage will occur to the cells 17 during removal thereof.

The tubular housing 44 is contained in casing 50 which includes an uppersection 51, a lower section 52, an intermediary flexible section 53 anda rear wall 54 through which the power cable 37 extends. Treatment fluidsupply conduit 66 which forms part of the fluid supply means 60, anddifferential pressure conduit 61 which forms part of the transferringmeans 90, hereafter discussed in detail, also extend through the rearwall 54. A flexible sleeve 57 is attached to the rear of the outercasing 50 and permits gross relative movement with respect to theremoval site 18.

To permit relative movement of the tool 43 with respect to tensioningmeans 70 to intermediary section 53 is flexible and is interposedbetween the upper section 51 and lower section 52, and may be in theform of a bellows adapted to permit tilting of the upper section 51 withrespect to the lower section 52. The front end 68 of the lower section52 is provided with the tensioning means 70 for maintaining the tissueto be removed under tension in the direction of arrow 71 (see FIG.during movement of the tool 43 in the direction of arrow 72 (see FIG. 4)to obtain a substantially continuous depth of removal with minimalinjury to the cells. The tensioning means 70 includes a plurality ofoutwardly curved flexible fingers or members 73 in spaced-apart relationsuch that its contacting edge 74 grips the tissue 16 and forces itoutwardly in the direction of the arrow 71 to hold it firm. Thetensioning means 70 is not necessary in all instances since it isdependent upon the portion of the human, the cells are being removedfrom as well as the depth of removal, plus the skill of the operator inperforming the grafting operation.

The ultrasonic motor 41 may be one of a variety of electromechanicaltypes, such as electrodynamic, piezoelectric and magnetostrictive. Theultrasonic motor for effecting tissue removal through hand directedtools of suitable configuration which are interchangeable with otherwork performing tools in acoustically vibrated material treating devicesmay be of the type disclosed in U.S. Pat. No. Re. 25,033, 3,075,288,3,076,904 and 3,213,537, and wherein each work tool is rigidly joined,in end-to-end relationship to a connecting body or acoustic impedancetransformer and to a transducer which may form an insert unit orassembly which is removably supported in a housing containing a coil insurrounding relationship to the transducer and receiving alternatingcurrent for producing an alternating electromagnetic field.

The transducer in the ultrasonic motor 41 is longitudinally dimensionedso as to have lengths which are whole multiples of half-wavelengths ofthe compressional waves established therein at the frequency of thebiassed alternating current supplied so that longitudinal loops ofmotion as indicated by arrow 16, occur both at the end of the insertunit 47 to which the tool 43 is rigidly connected. Thus, the optimumamplitude of longitudinal vibration and hyperaccelerations of tool 43 isachieved, and such amplitude is determined by the relationship of themasses of the tool 43 and insert unit 47 which may be made effective toeither magnify or reduce the amplitude of the vibrations received fromthe transducer.

Applicant has discovered in accordance with his copending patentapplication referred to above, that a tool having a sharp edge,vibrating ultrasonically, and gently pressed against a highly compliantsubstance, such as organic living tissue 16, will actually penetrate orshatter said substance whenever the peak acceleration of the sharp edgeis above the threshold range of the treated material. For substancessuch as human tissue it is found that if one uses a tool edge where thepeak acceleration is well over the value of 50,000 3, rapid removal oftissue is obtainable. By simultaneously employing gross motion of thevibratory tool along a plane substantially parallel to the surface ofthe very highly compliant material we obtain a repetition of themicrochopping process so that layers of tissue may be removed.

Applicant is well aware of the art of disrupting biological cells bymeans of intensely cavitating liquids such as is obtained by puttingsuch cells in a liquid suspension and then irradiating the liquid with abeam of ultrasonic vibration strong enough to produce vigorouscavitation. In this way blood cells may be hemolyzed in a very shorttime by means of cavitating liquid. But, if one takes the cells in theskin of ones finger and exposes them indefinitely by rubbing the fingertip against an ultrasonic tool of flat pistonlike output in the presenceof a liquid, one will experience a tingling, massagelike sensation,which is not unpleasant and all that happens superficially is thecleaning of the surface of the skin. Thus, those forces which willdisrupt cells in liquid suspension will have no such effect on livetissue such as human skin. But, as soon as a tool vibrating athyperintense accelerations whose output configuration is in accord withthe teachings herein is brought into direct contact with the tissue, theinteraction between the tool and the tissue causes the said tissue to bechopped or broken into small clusters and easily removed without damageto the underlying or surrounding tissue as well as the removed cellularmaterial.

The hand held ultrasonic motor illustrated in FIGS. 4 and 5, is employedand the tool 43 moves periodically in a plane substantially normal tothe layer of tissue 16 in the direction of arrow 72, so that its peakacceleration is well above 50,000 g, and which tool, when applied to thesuperficial biological tissue 16, will actually disintegrate same intosmall clusters or substantially individual viable cells 17 by way of themicrochopping action present.

It is important that the operation of cutting be performed withoutsignificant cavitation at the site, so as to avoid blasting the cellsinto a homogeneous dispersion. The suppression of cavitation ariseschiefly from the sharpness of the vibrating edge and the direction ofvibration, so that practically zero area is present in the cutting edge.In practice, it is the vibrating area which determines the amount ofcavitation.

The tool 43 may be in the form of a relatively flat metal member, asshown in FIGS. 4 and 5, thereby to provide a relatively long edge forcontact with the tissue or other highly compliant materials to which thevibrations are to be applied for effecting the removal thereof bymicrochopping. The tool 43 may be permanently attached to the end ofinsert unit 47, for example, by brazing solder or the like, or the toolmay be provided with a threaded stud (not shown) adapted to be screwedinto a tapped hole in the end of the insert unit 47 for effecting therigid connection of the tool to the stem.

Guard means in the form of hood 80, extending from the housing 44 isprovided in telescoping relationship to the insert unit 47 and toolmember 43 with its front end 81 in spaced relation a distance D to theedge 45 of the tool 43. As hereinafter explained this permits the userto control the thickness of the layer of tissue to be microchopped intosmall segments, cell clusters, or individual cells 17 and removed.

Means for Transferring the Fluidized Suspension Transferring meansprovides for the removal of the fluidized suspension 62 from the removalsite 18 to the grafting site 20 and in turn the depositing of the cellson the grafting site. The transferring means 90 mounted on the shelf 30includes a reservoir 91 having a cover 92 for retaining the fluidizedsuspension :62, and in which the cells 17 may settle to the bottom 93thereof to produce a concentration thereof. Pump means 95 mounted on theshelf 30 is connected to the reservoir 91 by a tube 96 extending throughthe cover 92 into the reservoir 91. By maintaining the reservoirsubstantially sealed the pump means 95 creates a differential pressurein the reservoir 91 for obtaining either a pumping in or out therefromof the fluidized suspension 62. The pump may have a two-way switch toconnect to pressure or suction outlet. Obviously other conventionalpumping means may be employed.

The conduit 61 is connected to a removal valve 97 which in turn isconnected to inlet tube 98 which extends into the reservoir 91 throughthe cover 92 a given distance. For the removal of the fluidizedsuspension 62 from the reservoir 91 an outlet tube 100 is provided andextends substantially to the bottom of the reservoir where a higherconcentration of cells 17 are contained. The outlet tube 100 isconnected to applicator valve 101 which in turn through applicator tube102 is connected to the depositing means 105.

In order to facilitate the removal of the microchopped tissue from theremoval site 18 the removal valve 97 is opened and the applicator valve101 is closed, and a suction force is applied by means of conduit 61 tothe ultrasonic motor 41. The conduit 61 is connected in any conventionalmanner (not shown) through the housing 44 and terminates in the hood 80so as to apply a suction force as indicated by the arrow 86 in FIG. 5.

To progressively cover a surface area and remove a layer of the organictissue therefrom the ultrasonic motor is moved in the direction of arrow72 so as to continually microchop the surface area and apply a suctionforce and a treatment fluid to the work site. The treatment fluid ispreferably an antiseptic so that the surface may be maintained free ofgerms. The treatment liquid is pressurized by the tool 43 which enhancesthe effectiveness of the liquid in mixing with the microchopped tissueand forming a suspension thereof. The suspension may flow by means ofgravity from the treated surface or a suction force may be applied andutilized adjacent the tool.

If desired the flow may be reversed and the liquid supplied by thepumping means through the opening defined between the inner surface ofthe guard means 80 and the tool 43 so as to permit the removal of theemulsified mixture through at least one of the branches 104 and channel108. The suction means illustrated in FIG. 3, may be employed and may beassisted by the ultrasonic pumping means 103 contained in the tool 43.The pumping means consisting of a number of ridges as in the form ofthreads actually apply a force in the direction of arrow 86 which forceassists in instantaneously cleaning the removal site. As such thecontinuous removal of the microchopped tissue from the surface may alsobe accomplished by combining the ultrasonic pumping action with thesuction supplied through the tool.

Ultrasonic pumping means 103 may be relied upon either alone or incombination with the suction means to remove the microchopped materialfrom the removal site. The pumping means 103 is employed when thechannel 108 and branches 104 are utilized as the removal duct and theultrasonic pumping means may consist of formations on the wall of thechannel 108, as for example, threads which direct the microchoppedparticles away from the removal site.

After a sufficient quantity of cells 17 have been removed from thetissue 16 the generator 36 is turned off as well as the fluid supplysource 64 such that the removal process is discontinued. It isappreciated that by the proper arrangement of well known equipment thecontinuous depositing of the cells on the grafting site may beaccomplished. As illustrated the removal valve 97 will be closed and theapplicator valve 101 opened to permit the removal of the fluidizedsuspension 62 from the reservoir 91 to the grafting site 20.

Since more treatment fluid might be utilized in forming the suspensionthan required in the actual application of the cells 17 to the graftingsite 20 means for forming a concentration of the cells 17 prior todepositing on the grafting site 20 may be employed. Although variouscommercial equipment may be employed to obtain the concentration withoutinjuring the cells, the invention illustrates a simple means ofobtaining this concentration by positioning the outlet tube 100 closeenough to the bottom 93 of the reservoir 91 so that the cells 17 thathave settled close to the bottom may be removed therefrom to provide ahigher concentration of cells on the grafting site.

Means for Depositing the Fluidized Suspension on a Grafting SiteDepositing means as illustrated in FIG. 6, is connected by theapplicator tube 102 to the transferring means 90. such that a continuoussupply of fluidized suspension 62 may be continuously or intermittentlyapplied to the grafting site 18. At the grafting site 18 it ispreferable to maintain a sterile condition to have the exposed areacovered with a preferably transparent cover or closure. This closure maybe flexible so as to permit the spraying of the fluidized cellsuniformly over the grafting site, so as to seed" it properly. Ifconditions require, a rigid cover may likewise be employed. There exista number of ways of physically depositing the fluidized suspension onthe grafting site 18 in accordance with the present invention. One formof which is to form a spray 106 bypassing the fluidized suspensionthrough a nozzle 107 adapted to be moved relative to the grafting siteso as to obtain a dispersion of the cells 17 thereon.

Since the treatment fluid acts as 'a carrier for the cells in almost allcases a degree of treatment fluid will be deposited on the graftingsite. If the cell concentration is sufficiently high the treatment fluidmay be left to run off with a certain percentage of cells. In contrast,if the fluidized suspension does not contain a substantial concentrationof cells then draining means 110 may be employed so that a substantialconcentration is assured to be retained thereon. The draining means 110may be in the form of a closure 111 having an open end with a peripheraledge 112 for engagement with the grafting site 18. The peripheral edge112 is provided with a series of slits 113 to facilitate the flow of thetreatment liquid 63 from the grafting site. The top 1 14 of the closurecontains a flexible member 115 which is secured to the applicator tube102 to permit relative movement in the direction of arrow 116 of nozzle107 while the closure 111 remains in a fixed position.

The grafting site 18 may be first coated with a layer of medication 120that serves the purposes of sterilizing and attracting the cells 17while the treatment liquid 63 runs off the grafting site 18.

Operation In accordance with this invention the human 15 is firstpositioned in place on the support means 12 with removal site 18 andgrafting site 20 both exposed for the removal of cellular tissue 17 fromone site and transplanting to the other site. The positioning means 25is brought into position so that the interrelated equipment is easilycontrolled to perform the grafting operation.

Initially the generator 36 is turned on and the intensity control 39 andfrequency control 40 are adjusted to obtain the proper degree ofvibratory energy in the removal means 35 at the output edge 45 of thetool 43. The frequency and intensity is selected and maintained at anenergy level below which substantial damage will occur to the cells 17during removal thereof. This does not preclude the fact that a certainsmall percent of the removed cells might be damaged and not take at thegrafting site. The removalmeans 35 is placed in position, as seen withrespect to FIGS. 1, 2 and 5, and the tool 43 penetrates the tissue 16until the front end 81 of the hood 80 engages the surface of the tissue16. The tensioning means 70 is then brought into engagement with thetissue 16 and laterally applied forces in the direction of arrow 71retains the skin under tension to assure a substantially continuousdepth of removal of fluidized suspension through conduit 61 and inlettube 98 into the reservoir 90. Means of tensioning the tissue 16 arealso contemplated within this invention such as surface freezing thetissue such that it is less deformable but still may be microchopped andtransplanted in accordance with this invention.

The depositing of the cells 17 on the grafting site 20 as illustrated inFIGS. 1, 2 and 6 may be carried on simultaneously with the removalprocess or some time thereafter. The time lapse will depend on a numberof factors, for example, if the cells are removed from one human to betransplanted to another it might be necessary to first treat the cellsin a solution for a period of time before depositing same on a differenthuman. If the cells 17 had been removed for a "cell bank and were frozenthen time to let the cells thaw out to roomltemperature might berequired. Another reason for permitting a period of time to elapse,unless a centrifuge is used, is the obtainment of a higher concentrationof cells per given volume than is obtained per same given volume whenthe cells are removed. By letting the cells 17 settle to the bottom 93of the reservoir 91 they are then extracted by means of outlet tube 100and transferred to the depositing means 105.

in forming the fluidized suspension 62 a treatment fluid 63 is providedas required from the fluid supply source 60 that travels through conduit65 to the removal site 18 and there enhances the removal of the cellswhich are microchopped into cell clusters or cells 17 and form a mixturewith the treatment fluid 63.

The fluidized suspension 62 is continuously removed and transferred viathe transferring means 65 to the grafting site 20. This is preferablyaccomplished by maintaining a differential of pressure as by applying asuction force from pump 95 which creates a vacuum in the sealedreservoir 91 and by having removal valve 97 open and applicator valve101 closed. The suction force is transmitted through conduit which pumpsthe fluidized suspension into the reservoir. For removal from thereservoir 91 the valve 97 is closed and the applicator valve 101 isopened with the cells 17 in the fluidized suspension 62 exiting from thereservoir 91 by the force applied by the pump 95. The depositing means105 may take various forms and shapes depending on the area of thegrafting site as well as the condition of the patient 15. As illustratedit includes a nozzle 107 from a spray 106 that includes both the cells17 and treatment fluid 63. If a concentration of cells 17 had beenformed by extracting from the reservoir 91 cells 17 at a greaterconcentration per given volume than initially pumped into the reservoirper same given volume then the draining means 110 might not be required.If the treatment fluid is too great then draining takes place byproviding the closure 111 with fine slits 113 to pennit the exiting ofthe treatment fluid while leaving a layer of cells 17 that will form anew layer of tissue on the human 15.

The nozzle 107 may be moved relative to the grafting site 20 until acomplete layer of cellular material is deposited thereon. For certainapplications a layer of medication 120 might first be placed on thegrafting site 20 to assure a proper seeding of the newly deposited cellsthereon. When transplants are to be performed covering large areas ofthe body the apparatus may be automated to the extent that thedepositing means and removal means automatically traverse areas of thebody and perform their functions substantially unattended.

Additional Embodiments of the Invention FlGS. 7 and 8, illustrate otherforms of tools that may be used to obtain the variety of vibrationalmotions for the removal of tissue in various locations without permanentdamage to the removed cellular material.

The tool 43a illustrated in FIG. 7, has a passageway 121a, which may beof circular cross-sectional area and the output edge 45a of the tool maybe chisel shaped to provide a minimal of contacting area with the tissue16a at the removal site 18a, to maintain the creation of cavitationthereat at a minimum. The hood 80a is in coaxial alignment with the tool43a and the front end 81a engages the tissue 16a to control the depth ofcut as the tool is moved in the direction of arrow 72a. The longitudinalvibratory energy is applied in the direction of arrow 76a and a routingor planing action is obtained with the relative movement between thetool and removal site.

FIG. 8, illustrates a tool 43b having a chisel shaped output edge 45bangularly disposed to the tissue 16b at the removal site 18b, with theguard 80b having an opening 122!) to permit the tool to extendtherethrough a preselected distance. With this tool arrangement weobtain an ultrasonic microplaning removal of the tissue 16b as theultrasonic vibrations are applied in the direction of arrow 76b and thefront end 81b of the guard 80b engages the tissue 16b to control thedepth of cut.

8 CONCLUSION From the above disclosure, it is evident that the methodand apparatus of this invention embraces an interrelated series ofdevices and instruments which can be advantageously employed foreffectively grafting of tissue. In accordance with the invention we havethe removal of live epidermal cellular tissue from one site on a personsbody and the application of that viable tissue to another site in thesame or different human. The use of the microchopping principle combinedwith sterile pumping means, permits the use of a self-contained systemwherein grafting over large body areas (cases of severe burns, forinstance) may be accomplished readily and easily.

This invention also contemplates the establishment of a cell bank" inthat the removed cells may remain in solution under controlledconditions until such time as required and then deposited on thegrafting site. Accordingly, the process of grafting in accordance withthis invention may be on a continuous or intermittent basis dependingupon the schedule of events and the needs of the patient.

The treatment fluid is preferably an antiseptic solution so that thework site may remain not only free of microchopped tissue but sterile atthe same time. The liquid is supplied to float away" the removed tissueand also maintain the work site at a controlled temperature as not tooverheat the surrounding tissue and possibly cause permanent damagethereto. The necessity of cooling the removal or work site will bedirectly related to the type of tissue being removed. An additionalfactor to be considered is the size of the surface area and thickness ofthe layer to successive layers to be removed. If desired the treatmentfluid may be supplied at a preselected temperature just for thispurpose.

Although the previously described embodiments of the invention have allinvolved the removal of tissue from organic structures, it is apparentthat the method and apparatus embodying the invention may be employedfor removing any other material of relatively low compliance, byintroducing elastic vibrations above the determined threshold thereofwhich will generally exceed 50,000 g.

Although illustrative embodiments of the invention have been describedin detail herein with reference to the accompanying drawings, it is tobe understood that the invention is not limited to those preciseembodiments, and that various changes and modifications may be effectedtherein without departing from the scope or spirit of the invention,except as defined in the appended claims.

I claim:

1. A method of grafting tissue to a human, comprising the steps of A.removing a layer of tissue from a portion of the human in the form ofcells utilizing ultrasonic energy, by

l. vibrating a tool member having an output edge to provide peakaccelerations of at least 50,000 g,

2. engaging said output edge of said vibrating tool member with thesurface of said tissue to transmit said vibrations to the tissue inengagement therewith, and

. microchopping said tissue from said human portion by progressivelymoving said output edge relative to the surface of said tissue such thatthere is a substantial component of relative motion perpendicular tosaid edge, whereby said layer of tissue is removed from said human,

B. forming a fluidized suspension containing said cells, and

C. depositing said cells of said fluidized suspension on a grafting siteto form a new layer of tissue on said human.

2. A method as in claim 1, further including the step of selecting andmaintaining the frequency and intensity of said ultrasonic energy at alevel below which substantial damage will occur to said cells duringremoval thereof.

3. A method as in claim 1, further including the step of transferringsaid fluidized suspension to said grafting site prior to depositing saidcells thereon.

4. A method as in claim 3, wherein the step of transferring said cellsincludes simultaneously applying suction to said ultrasonically treatedportion to remove said fluidized suspension therefrom.

5. A method as in claim 3, further including the step of draining thefluid of said fluidizedsuspension from said grafting site to leave asubstantial concentration of said cells thereon.

6. A method as in claim 1, wherein the step of depositing said cellsincludes spraying the fluidized suspension onto the grafting site soasto obtain a dispersion of said cells thereon.

7. A method as in claim 1, wherein the'step of forming a fluidizedsuspension includes the step of supplying a treatment fluid to saidportion of the human adapted to be treated with ultrasonic energy forenhancing the removal of said cells, and forming said fluidizedsuspension.

8. A method as in claim 1, further including the step of forming aconcentration of said cells prior to depositing said cells on saidgrafting site to form a concentrated layer of Cells thereon, v H.

9. A method as in claim 8, wherein the step of forming saidconcentration includes the steps of a. delivering said fluidizedsuspension to a reservoir, and

b. extracting from said reservoir said cells at a greater concentrationper given volume than initially pumped into said reservoir per saidgiven volume in said fluidized suspension.

10. A method as in claim 1, further including the step of firstpreparing the grafting site for the application of said cells thereon toenhance the grafting operation.

11. A method as in claim 1, further including the step of maintainingthe tissue to be removed under tension to obtain a substantiallycontinuous depth of removal.

12. A method as in claim 1, further including the step of controllingthe depth of removal of said layer of tissue during the relativemovement between said human and tool member.

13. A method as in claim 12, wherein said thickness of tissue removed iscontrolled by providing a guard having a bottom end in substantiallyparallel spaced relation to the output edge of said tool member, wherebythe thickness of the layer of tissue to be removed is controlled.

14. A method as in claim 1, wherein said step of forming a fluidizedsuspension includes the steps of a. supplying a treatment fluid to thetreated surface so that contact of said output edge with the treatedsurface pressurizes the fluid for enhancing the effectiveness of theliquid in mixing with the microchopped tissue and forming a suspensionthereof, and

b. simultaneously applying suction to said treated surface adjacent saidtool member to remove said suspension from the surface.

15. A method as in claim 14, wherein the treatment fluid is supplied tothe tissue surface and the suction is applied to the tissue surface atspaced apart locations between which at least a portion of the vibratedtool member is interposed so that the suction induces the treatmentfluid to flow between said vibrated tool member and the tissue surfacefor ensuring the continuous mixing and the removal of said suspension.

16. The method of grafting tissue to a human, comprising the steps of A.removing a layer of tissue from a portion of a human in the form ofcells utilizing ultrasonic energy, by

l. vibrating a tool member having an output edge to provide peakaccelerations of at least 50,000 g,

2. engaging said output edge of said vibrating tool member with thesurface of said tissue to transmit said vibrations to the tissue inengagement therewith,

. microchopping said tissue from said human by progressively moving saidoutput edge relative to the surface of said tissue such that there is asubstantial component of relative motion perpendicular to said edge,whereby said layer of tissue is removed from said human,

4. maintaining the tissue to be removed under tension to obtain asubstantially continuous depth of removal, and

5. controlling the depth of removal of said layer of tissue during therelative movement between said humanand tool member,

B. selecting and maintaining the frequency and intensity of saidultrasonic energy at a level below which permanent damage will occur tosaid removed cells and the surrounding tissue,

C. supplying a treatment fluid to said portion of the human treated withultrasonic energy for enhancing theremoval of said cells and forming afluidized suspension containing a mixture of said cells and treatmentfluid,

D. transferring said fluidized suspension to a grafting site by applyinga suction force to said ultrasonically treated portion to remove saidtreatment fluid therefrom, and

E. depositing said cells on said grafting site whereby said graftedcells form a new layer of tissue on said grafting site.

17. A method as in claim 16, further including the steps of a. firstpreparing the grafting site for the application of said cells thereon toenhance the grafting operation, and

b. extracting from said fluidized suspension concentration of said cellsprior to transferring said cells to said grafting site.

18. A method as in claim 17, wherein the step of depositing said cellsincludes spraying said fluidized suspension onto said grafting site soas to obtain a dispersion of said cells thereon.

19. A method of grafting tissue from a removal site to a grafting siteof a human, with an ultrasonic instrument having a tool member with anoutput edge for engagement with the tissue to be removed, comprising thesteps of A. supporting said human in a position wherein the removal andgrafting sites are exposed,

B. positioning said ultrasonic instrument in energy transferringrelationship to said removal site wherein said tool member engages saidtissue,

C. removing a layer of tissue from the removal site in substantiallycellular form by progressively moving said ultrasonic instrumentrelative to the surface of said removal site, said step of removing alayer of tissue further includes,

1. vibrating said output edge to provide peak accelerations of at least50,000 g,

2. microchopping said tissue from said human by progressively movingsaid output edge relative to the surface of said tissue such that thereis a substantial component of relative motion perpendicular to saidedge, whereby said layer of tissue is removed from said human,

. maintaining the tissue to be removed under tension to obtain asubstantially continuous depth of removal, and

controlling the depth of removal of said layer of tissue during therelative movement between said human and tool member,

D. forming a fluidized suspension containing said removed cells byproviding a treatment fluid to said work site for forming saidsuspension,

E. transferring said suspension containing said cells to a grafting siteadapted to receive said cells thereon, and

F. depositing said cells on said grafting site, whereby the graftedcells will form a new layer of tissue on said graft- A. means forultrasonically removing a layer of tissue from a portion of a human inthe form of cells, said means for ultrasonically removing a layer oftissue includes 1. a tool member having an output edge for engagementwith the layer of tissue of said portion as it is moved relativethereto,

2. vibration generating means coupled to said tool member to effectvibration of the latter at a high frequency and with peak accelerationsof at least b 50,000g, so as to microchop said tissue into particles asmunicating with said transferring means for forming a concentration ofsaid cells prior to depositing said cells on said grafting site.

ing said concentration includes ill the vibrating tool is moved relativeto said tissue surface, and

B. means for forming a fluidized suspension containing said cells, saidmeans of forming said fluidized suspension includes means for supplyinga treatment fluid to the tissue surface adjacent said vibrated toolmember so that contact of said vibrated tool member pressurizes theliquid for enhancing the effectiveness of the fluid in mixing with themicrochopped tissue particles and forming said fluidized suspension,

C. means for transferring said cells in said fluidized suspension to agrafting site adapted to receive said cells thereon, and

D. means communicating with said transferring means adapted fordepositing a layer of said cells on said grafting site to form a newlayer of tissue thereon.

21. Apparatus as in claim 20, further including means for selecting andcontrolling the frequency and intensity of said ultrasonic means at alevel below which substantial permanent damage will occur to said cellsduring removal thereof.

22. Apparatus as in claim 20, wherein said means adapted for depositingsaid cells includes means for spraying the fluidized suspension ontosaid grafting site so as to obtain a dispersion of said cells thereon toform said new layer of tissue.

23. Apparatus as in claim 22, further including means adapted fordraining the fluid of said fluidized suspension from said grafting siteto leave a substantial concentration of said cells thereon.

24. Apparatus as in claim 20, wherein said means for forming saidfluidized suspension includes means adapted for supplying a treatmentfluid to said portion of the human adapted to be treated with saidultrasonic energy for enhancing the removal of said cells, and formingsaid fluidized suspension.

25. Apparatus as in claim 24, wherein said means for transferring saidcells includes means adapted for applying suction to said ultrasonicallytreated portion to remove said fluidized suspension therefrom.

26. Apparatus as in claim 20, further including means com- 27. Apparatusas in claim 26, wherein said means for forma. a reservoir for retainingsaid fluidized suspension, and

b. means for extracting from said reservoir said cells for transferringto said grafting site at a greater concentration per given volume thaninitially pumped into said reservoir per said given volume.

28. Apparatus as in claim 29, and further including control meansengageable with said vibration generating means for controlling thethickness of said layer of tissue microchopped from the surface of thehuman.

29. Apparatus in claim 28, and further including means adapted formaintaining the tissue to be removed under tension during movement ofsaid tool member relative thereto, to obtain a substantially continuousdepth of removal.

30. Apparatus for grafting tissue to a human, comprising A. means forultrasonically removing a layer of tissue from a portion of a human inthe fonn of cells, said means for ultrasonically removing a layer oftissue includes 1. a tool member having an output edge for engagementwith the layer of tissue of said portion as it is moved relativethereto,

2. vibration generating means coupled to said tool member to effectvibration of the latter at a high frequency and with peak accelerationsof at least 50,000 3, so as to microchop said tissue into particles asthe vibrating tool is moved relative to said tissue surface, and

18. means for selecting and controlling the frequency and intensity ofsaid ultrasonic means at a level below which permanent damage will occurto said removed cells and the surrounding tissue,

C. means for applying a treatment fluid to said portion of the humanadapted to be treated with ultrasonic energy for enhancing the removalof said cells and forming a fluidized suspension,

D. means for transferring said cells of said fluidized suspension to agrafting site, including means for applying suction to saidultrasonically treated portion to remove said fluidized suspensiontherefrom,

E. means communicating with said means for transferring said cells andadapted for depositing same on said grafting site, and F. means adaptedfor draining said treatment fluid from said

1. A method of grafting tissue to a human, comprising the steps of A.removing a layer of tissue from a portion of the human in the form ofcells utilizing ultrasonic energy, by
 1. vibrating a tool member havingan output edge to provide peak accelerations of at least 50,000 g, 2.engaging said output edge of said vibrating tool member with the surfaceof said tissue to transmit said vibrations to the tissue in engagementtherewith, and
 3. microchopping said tissue from said human portion byprogressively moving said output edge relative to the surface of saidtissue such that there is a substantial component of relative motionperpendicular to said edge, whereby said layer of tissue is removed fromsaid human, B. forming a fluidized suspension containing said cells, andC. depositing said cells of said fluidized suspension on a grafting siteto form a new layer of tissue on said human.
 2. engaging said outputedge of said vibrating tool member with the surface of said tissue totransmit said vibrations to the tissue in engagement therewith, and 2.vibration generating means coupled to said tool member to effectvibration of the latter at a high frequency and with peak accelerationsof at least 50,000 g, so as to microchop said tissue into particles asthe vibrating tool is moved relative to said tissue surface, and B.means for selecting and controlling the frequency and intensity of saidultrasonic means at a level below which permanent damage will occur tosaid removed cells and the surrounding tissue, C. means for supplying atreatment fluid to said portion of the human adapted to be treated withultrasonic energy for enhancing the removal of said cells and forming afluidized suspension, D. means for transferring said cells of saidfluidized suspension to a grafting site, including means for applyingsuction to said ultrasonically treated portion to remove said fluidizedsuspension therefrom, E. means communicating with said means fortransferring said cells and adapted for depositing same on said graftingsite, and F. means adapted for draining said treatment fluid from saidgrafting site to leave a substantial concentration said cells thereon,whereby the grafted cells form a new layer of tissue on said graftingsite.
 2. vibration generating means coupled to said tool member toeffect vibration of the latter at a high frequency and with peakaccelerations of at least 50,000g, so as to microchop said tissue intoparticles as the vibrating tool is moved relative to said tissuesurface, and B. means for forming a fluidized suspension containing saidcells, said means of forming said fluidized suspension includes meansfor supplying a treatment fluid to the tissue surface adjacent saidvibrated tool member so that contact of said vibrated tool memberpressurizes the liquid for enhancing the effectiveness of the fluid inmixing with the microchopped tissue particles and forming said fluidizedsuspension, C. means for transferring said cells in said fluidizedsuspension to a grafting site adapted to receive said cells thereon, andD. means communicating with said transferring means adapted fordepositing a layer of said cells on said grafting site to form a newlayer of tissue thereon.
 2. A method as in claim 1, further includingthe step of selecting and maintaining the frequency and intensity ofsaid ultrasonic energy at a level below which substantial damage willoccur to said cells during removal thereof.
 2. engaging said output edgeof said vibrating tool member with the surface of said tissue totransmit said vibrations to the tissue in engagement therewith, 2.microchopping said tissue from said human by progressively moving saidoutput edge relative to the surface of said tissue such that there is asubstantial component of relative motion perpendicular to said edge,whereby said layer of tissue is removed from said human,
 3. maintainingthe tissue to be removed under tension to obtain a substantiallycontinuous depth of removal, and
 3. microchopping said tissue from saidhuman by progressively moving said output edge relative to the surfaceof said tissue such that there is a substantial component of relativemotion perpendicular to said edge, whereby said layer of tissue isremoved from said human,
 3. A method as in claim 1, further includingthe step of transferring said fluidized suspension to said grafting siteprior to depositing said cells thereon.
 3. microchopping said tissuefrom said human portion by progressively moving said output edgerelative to the surface of said tissue such that there is a substantialcomponent of relative motion perpendicular to said edge, whereby saidlayer of tissue is removed from said human, B. forming a fluidizedsuspension containing said cells, and C. depositing said cells of saidfluidized suspension on a grafting site to form a new layer of tissue onsaid human.
 4. A method as in claim 3, wherein the step of transferringsaid cells includes simultaneously applying suction to saidultrasonically treated portion to remove said fluidized suspensiontherefrom.
 4. maintaining the tissue to be removed under tension toobtain a substantially continuous depth of removal, and
 4. controllingthe depth of removal of said layer of tissue during the relativemovement between said human and tool member, D. forming a fluidizedsuspension containing said removed cells by providing a treatment fluidto said work site for forming said suspension, E. transferring saidsuspension containing said cells to a grafting site adapted to receivesaid cells thereon, and F. depositing said cells on said grafting site,whereby the grafted cells will form a new layer of tissue on saidgrafting site.
 5. controlling the depth of removal of said layer oftissue during the relative movement between said human and tool member,B. selecting and maintaining the frequency and intensity of saidultrasonic energy at a level below which permanent damage will occur tosaid removed cells and the surrounding tissue, C. supplying a treatmentfluid to said portion of the human treated with ultrasonic energy forenhancing the removal of said cells and forming a fluidized suspensioncontaining a mixture of said cells and treatment fluid, D. transferringsaid fluidized suspension to a grafting site by applying a suction forceto said ultrasonically treated portion to remove said treatment fluidtherefrom, and E. depositing said cells on said grafting site wherebysaid grafted cells form a new layer of tissue on said grafting site. 5.A method as in claim 3, further including the step of draining the fluidof said fluidized suspension from said grafting site to leave asubstantial concentration of said cells thereon.
 6. A method as in claim1, wherein the step of depositing said cells includes spraying thefluidized suspension onto the grafting site so as to obtain a dispersionof said cells thereon.
 9. A method as in claim 8, wherein the step offorming said concentration includes the steps of a. delivering saidfluidized suspension to a reservoir, and b. extracting from saidreservoir said cells at a greater concentration per given volume thaninitially pumped into said reservoir per said given volume in saidfluidized suspension.
 10. A method as in claim 1, further including thestep of first preparing the grafting site for the application of saidcells thereon to enhance the grafting operation.
 11. A method as inclaim 1, further including the step of maintaining the tissue to beremoved under tension to obtain a substantially continuous depth ofreMoval.
 12. A method as in claim 1, further including the step ofcontrolling the depth of removal of said layer of tissue during therelative movement between said human and tool member.
 13. A method as inclaim 12, wherein said thickness of tissue removed is controlled byproviding a guard having a bottom end in substantially parallel spacedrelation to the output edge of said tool member, whereby the thicknessof the layer of tissue to be removed is controlled.
 14. A method as inclaim 1, wherein said step of forming a fluidized suspension includesthe steps of a. supplying a treatment fluid to the treated surface sothat contact of said output edge with the treated surface pressurizesthe fluid for enhancing the effectiveness of the liquid in mixing withthe microchopped tissue and forming a suspension thereof, and b.simultaneously applying suction to said treated surface adjacent saidtool member to remove said suspension from the surface.
 15. A method asin claim 14, wherein the treatment fluid is supplied to the tissuesurface and the suction is applied to the tissue surface at spaced apartlocations between which at least a portion of the vibrated tool memberis interposed so that the suction induces the treatment fluid to flowbetween said vibrated tool member and the tissue surface for ensuringthe continuous mixing and the removal of said suspension.
 16. The methodof grafting tissue to a human, comprising the steps of A. removing alayer of tissue from a portion of a human in the form of cells utilizingultrasonic energy, by
 17. A method as in claim 16, further including thesteps of a. first preparing the grafting site for the application ofsaid cells thereon to enhance the grafting operation, and b. extractingfrom said fluidized suspension concentration of said cells prior totransferring said cells to said grafting site.
 18. A method as in claim17, wherein the step of depositing said cells includes spraying saidfluidized suspension onto said grafting site so as to obtain adispersion of said cells thereon.
 19. A method of grafting tissue from aremoval site to a grafting site of a human, with an ultrasonicinstrument having a tool member with an output edge for engagement withthe tissue to be removed, comprising the steps of A. supporting saidhuman in a position wherein the removal and grafting sites are exposed,B. positioning said ultrasonic insTrument in energy transferringrelationship to said removal site wherein said tool member engages saidtissue, C. removing a layer of tissue from the removal site insubstantially cellular form by progressively moving said ultrasonicinstrument relative to the surface of said removal site, said step ofremoving a layer of tissue further includes,
 20. Apparatus for graftingtissue to a human, comprising A. means for ultrasonically removing alayer of tissue from a portion of a human in the form of cells, saidmeans for ultrasonically removing a layer of tissue includes 21.Apparatus as in claim 20, further including means for selecting andcontrolling the frequency and intensity of said ultrasonic means at alevel below which substantial permanent damage will occur to said cellsduring removal thereof.
 22. Apparatus as in claim 20, wherein said meansadapted for depositing said cells includes means for spraying thefluidized suspension onto said grafting site so as to obtain adispersion of said cells thereon to form said new layer of tissue. 23.Apparatus as in claim 22, further including means adapted for drainingthe fluid of said fluidized suspension from said grafting site to leavea substantial concentration of said cells thereon.
 24. Apparatus as inclaim 20, wherein said means for forming said fluidized suspensionincludes means adapted for supplying a treatment fluid to said portionof the human adapted to be treated with said ultrasonic energy forenhancing the removal of said cells, and forming said fluidizedsuspension.
 25. Apparatus as in claim 24, wherein said means fortransferring said cells includes means adapted for applying suction tosaid ultrasonically treated portion to remove said fluidized suspensiontherefrom.
 26. Apparatus as in claiM 20, further including meanscommunicating with said transferring means for forming a concentrationof said cells prior to depositing said cells on said grafting site. 27.Apparatus as in claim 26, wherein said means for forming saidconcentration includes a. a reservoir for retaining said fluidizedsuspension, and b. means for extracting from said reservoir said cellsfor transferring to said grafting site at a greater concentration pergiven volume than initially pumped into said reservoir per said givenvolume.
 28. Apparatus as in claim 20, and further including controlmeans engageable with said vibration generating means for controllingthe thickness of said layer of tissue microchopped from the surface ofthe human.
 29. Apparatus in claim 28, and further including meansadapted for maintaining the tissue to be removed under tension duringmovement of said tool member relative thereto, to obtain a substantiallycontinuous depth of removal.
 30. Apparatus for grafting tissue to ahuman, comprising A. means for ultrasonically removing a layer of tissuefrom a portion of a human in the form of cells, said means forultrasonically removing a layer of tissue includes
 31. Apparatus as inclaim 30, wherein said means for depositing said cells includes a nozzleadapted to be moved relative to the grafting site so as to obtain adispersion of said cells thereon.